Harvesting heads for agricultural harvesters that are configured to harvest row crops typically have devices called row units. Row units are the mechanical assemblies that are configured to receive a row of crop plants, and to harvest them. Row units, such as cornrow units, also include structures to strip away part of the unwanted crop material, such as the plant's stalk.
In its simplest configuration, a cornrow unit, such as the one illustrated herein, includes 2 elongate cantilevered arms that extend forwardly and generally horizontally in the direction of travel. These arms, fixed together at the rear of the arms, define a gap there between that is configured to receive a single row of crop plants. The arms support gathering chains, endless chains on each arm that gather the crop plants that are directed into the gap between the arms and pull them rearward.
Stalk rolls (also known as snapping rolls) are provided underneath the row unit arms to grasp the plant's talk as it is pulled rearward by the gathering chains and to pull the stalk downward. And deck plates which are disposed on the upper surfaces of the arms define an adjustable gap that permits the plant stalks to be pulled downward and ejected into the ground but will not permit ears of corn to pass there between and be lost. Instead, the ears of corn are “snapped” from the plant stalk and are carried rearward by the gathering chains into the agricultural harvester.
A gearbox is bolted to the rear of the row unit arms—typically between them—to drive the gathering chains and the stalk rolls. The gearbox or the ends of the row unit arms are bolted to a laterally extending bar in the harvesting head that supports the row units.
Row units travel through the field quite close to the ground in order not to miss any portion of the crop. There are problems, however, with this arrangement. As the harvesting head of the agricultural harvester traverses the ground, the tips of the row units may drop low enough to skid along the surface of the ground or (worse) dig into the ground. When this happens, the row unit arms, which are camped levered forward from the frame of the harvesting head are prone to bend or break. It is a continuing concern of agricultural engineers to make row units as light as possible to reduce power consumption and wait, but not so light that they are damaged.
The present application is directed to the problem of providing row units with row unit arm assemblies that are both light and strong.